In recent years, wireless power transmission systems have undergone broad technical development. Incidentally, if a foreign substance such as a piece of metal is present in the range in which a power transmitting apparatus can transmit power, an eddy current will flow in the foreign substance and unintended heating will occur. For this reason, in a wireless power transmission system, it is necessary to perform appropriate power transmission to a power receiving apparatus while giving consideration to the influence on foreign substances. For example, Japanese Patent Laid-Open No. 2013-17379 (Patent Literature 1) proposes a technique of providing a power receiving apparatus with a circuit for measuring the Q-value of the power receiving antenna and performing foreign substance detection using the Q-value measurement result.
However, in the technique disclosed in Patent Document 1 above, there is a problem in that the circuit for measuring the Q-value of the power receiving antenna needs to be newly provided and the cost will increase.